Vertical Growing in a Nutshell

“Noob” growers often scratch their heads when they first hear about the concept of vertical growing. “Don’t plants grow upwards normally?” they ask. So let’s get the difference between horizontal (regular) growing and vertical growing sorted out straight away.

Horizontal growing

Vertical growing

Horizontal growing is how most gardeners (indoor and outdoor) work. Plants are grown in pots or systems along a horizontal plane, and the grow light/s are positioned above the plants, mounted in a reflector so that the light gets beamed down to where it’s needed.

Vertical growing involves positioning the plants in a 360-degree formation around a grow lamp (sometimes in a cool tube but using no reflector). The general idea is that you maximize the use of the height in your garden, and make the most all that precious light energy without the use of reflectors. Plants in vertical growing systems tend to be a lot smaller, meaning shorter veg times but far greater plant numbers.

Growers’ Backgrounds

Everest: Okay guys, thanks for joining us. Now I know you’ve been blasting each other on the forums and you’re probably bursting at the seams to get going with this one, but first, can you each talk a little about your growing experience so the folks out there have an idea about where you’re both coming from?

Ian: Sure—I’ve been growing indoors for just over ten years. I started with potting soils, played around with most hydroponic systems (NFT, drip, ebb and flow, aeroponics) and a huge variety of growing media, and now I grow with coir using pots in a homemade drip system. I’ve stood by while some of my friends tried, and mostly failed, with vertical growing systems and even helped a few manage them for a while, which is why I would never recommend one to an interested grower.

Everest: Easy now Ian, we’ll get to all that. What about you Simon?

Simon: Well I’ve been growing on and off for around 15 years. I started with soil; I think 99% of people do. Then my local grow store switched me on to coco. I’ve tried clay pebbles too, sometimes mixed with rock wool croutons. I’ve run ebb and flow, NFT, drippers you name it. I’ve tried and failed with aeroponics but, to be honest, it was down to my ineptitude rather than anything else. But unlike Ian I don’t dismiss a technique out of hand just because it didn’t work for me. I’ve been running an Ecosystem since they came on the market. I’ve got my best results ever from vertical growing—it rocks!

Ian: Hang on, I’m not ‘dismissing’ vertical growing and, no disrespect, but personal bests are relative to the person. I’m just here to argue that vertical growing systems are not all they’re cracked up to be. I’m not even going to bring into the argument the phenomenal cost of vertical systems, which is enough to put a lot of people off. I want to focus on the practicality of using these systems, and why they suck.

Practical Considerations

Simon: There you go again. Why do you have to say “they suck” like that? I’m here to, hopefully, participate in an intelligent discussion about vertical growing. You mentioned practicality. Well, first off, vertical growing systems are a cinch to set up. Take the Ecosystem and Ecosystem 2 for example. They are ready to go gardens: lights, growing media, irrigation, reservoir—ready, steady, grow. All you need to do is take care of the growing environment.

Ian: You make it sound so easy! Ha ha. But ok, this I’ll give you. Some vertical growing systems are very quick and easy to set up. Others though, are a horrible arduous chore! I’ve had the joy of filling a Coliseum—300 plant sites with 3 x 1000 W lights—with a 265 gallon mix of perlite and vermiculite and, boy oh boy, it was a nightmare! It took the two of us the best part of four hours, and I’m not talking transplanting, just filling the system with growing media! Never again!

Vertical hydroponic systems are great for growing leafy herb crops in a small space as well as fruits and flowers. Note how this grower chose not to utilize all the planting sites.

Simon: You’re talking about growing 300 plants. And duh, guess what, that involves preparing 300 plant sites. Sorry if you’re work shy Ian but, of course, it’s going to take some labor to prepare! If I could find a system that filled itself with grow media, emptied itself, and replanted itself, I’d probably go for that, but …

Ian: Now you’re being both dumb and facetious Simon. But at least you’ve made a salient point against vertical growing on my behalf! Aren’t we really talking about making the most from your grow lights—in this instance, 3 x 1000 W. Don’t we need to ask why 3 x 1000 W grow lights should necessitate 300 plants in the first place!? It could just as easily light 18 large plants in five-gallon pots, spread over three, 5 x 5 ft ebb and flow trays. It’s going to take me … what … 10 minutes to fill 18 pots, not four hours to fill 300 plant sites?

Simon: And how long to veg up those “18 large plants” you mentioned?

Ian: Well, with six plants under a 1000 W … 10 days, maybe two weeks?

Basil gone crazy in a Coliseum! Regular cut and come again harvesting will keep this wall of basil in check!

Simon: (Cackles) two weeks! That’s ridiculous! Compare it with my two-day veg time for micro-plants in a vertical grow. My crop cycles are nearly half a month less than yours. You’re getting what … a maximum or five crops a year, whereas I’m always pushing six, using less energy too as I don’t have to have veg lights on for 18 hours a day for two weeks—ouch! I wouldn’t like to see your electricity bills!

Ian: But what about your plant numbers dude! They must be astronomical! In vertical systems you need anywhere between 80–300 identical cuttings for a two- or three-light system. In my four-light room I grow 24 plants, and to prepare for this I take 40 cuttings from one donor plant. Seems a little excessive to some but I only select the healthiest 24 with identical branch and node formation, the others I trash or give away. This selective approach helps me achieve a very uniform crop, level canopy and consistent yields.

Everest: That’s all cool and the gang, but what about Simon’s point on veg times and energy usage? Doesn’t that concern you at all, Ian?

Ian: Well it all sounds so wonderful in theory doesn’t it? Veg under metal halides for a few days and transplant into the system and bosh—straight into flower on a 12/12 light cycle. That’s what my buddy did and he found, due to the small veg time in the system, that some plants did not establish well enough and got left behind while others over grew and over shadowed them.

Simon: I’ve had that problem too. I overcame it by making sure that roots were simply exploding out of the rock wool cubes before transplanting into slabs. (Not just one or two.) I make sure those slabs have been pH adjusted and I water in my transplants individually with some CANNA Rhizotonic and a mild, balanced bloom formulation at around EC 0.8 and pH 5.5 – 5.8. I veg in the slabs horizontally for a couple of days, allowing the cuttings time to anchor in a little. Some plants will always outperform others—that’s natural. But I still end up with a beautiful canopy, either way. The trick with vertical growing is to select the right sort of phenotype that doesn’t stretch and get all gangly. You need to really know what you’re dealing with.

Ian: Yeah, yeah, but back to uniformity of cuttings for a moment; it’s easier said than done. And it’s so important to get right with vertical gardens, where plants are grown very close together and need to be kept small and squat, so identically sized cuttings are even more essential. This means for a 300-plant system I would have to take at least 400 cuttings (preferably 500), which means needing loads of huge donor plants to take them from. For my four-light room, I have a two-tiered shelved propagation tent, which is 4 x 2 x 4 ft, this houses two short stocky mother plants and my cuttings. To take a batch of 400 cuttings you’d need an additional two-light grow room! How is that saving space, let alone energy? It’s just shifting it all somewhere else! The whole thing’s a poorly marketed gimmick.

Simon: Yeah, you need lots of uniform cuttings to make vertical growing work, and not all plant species or varieties are suitable. Yeah, you need to know what you’re doing. I wouldn’t suggest this technique to a beginner. But the fact remains, I’m pulling six crops a year, you’re pulling four or five. I produce the 140 cuttings I need for my Ecosystem from two bushy mother plants under two x 400 W metal halides. Perhaps they aren’t always as uniform as I’d like though. More mother plants would help. I root them in several standard propagators under two banks of High Output T5 Fluorescents. And I veg them into rock wool slabs for two days under 250W metal halides.

The Ecosystem 2 boasts many improvements over its predecessor including a separate reservoir, increased number of plant sites, and more versatility with choice of growing media.

Ian: But two days isn’t enough veg time. The plants can’t lay down good foundations for their flowering cycle in such a short space of time. Also, wouldn’t you agree that with vertical growing it’s not about less work for the grower, it’s more that all the work shifts to propagation? Stressing over hundreds and hundreds of cuttings is not my idea of enjoyable indoor gardening. I’d rather be chilling and admiring my plants in my flat bed garden.

Simon: Well I guess we’re going to have to agree to differ on that one. Chill all you want with your five crops a year. I’ll happily “stress” over my six crops a year, thanks very much!

Ian: Yeah, I know yearly yields can be increased with short veg times, but six crops a year can be done with sea-of-green growing in horizontal gardens too, not just in fancy vertical systems. I’ve played around with higher plant numbers using ebb and flow trays, and can appreciate the quicker turn around, but as I’ve already said, the time and effort invested in preparing the garden and propagating the plants to get these larger yields is not worth the effort in my humble opinion.

Cool Tubes

Everest: Okay, let’s move on to another key component of vertical systems: cool tubes. Most vertical systems use glass air-cooled tubes to remove the heat from the lamp so the plants can bask closely to the light.

Ian: Yeah, but surely these tubes lower the amount and quality of light reaching the plants? I chatted to the guy at my grow store about this and he reckons that curved glass reduces light intensity by around 5% in comparison to flat glass which is around 3% compared to the open style reflector. Also, light tubes are not user friendly; I like to veg and finish my plants with metal halide lamps, using HPS in-between. Ever tried to swap out the lamps on a vertically mounted cool tube when there are loads of plants in the system? Trust me, it’s not easy.

Simon: Sure, glass stops UV (which promotes the development of essential oils) and diminishes light intensity a little, but this is all more than counteracted by the fact that you can get your lights closer to your plants. Also, many Ecosystem growers here in Montreal don’t use cool tubes at all; they simply drive lots of fresh air through the system. I’ve seen plants just inches away from 1000 W lamps! With enough air movement, they’re okay.

Ian: You’ve got to wonder about the potential for all those plants crowding out a cylindrical vertical growing system; there’s a fixed distance between the light and the canopy, which cannot be adjusted on most designs. This means as the plants grow from the system toward the light, the total canopy size decreases as the crop grows! Think about it. Most vertical systems are circular; as the crop grows it gets closer to the light so the circular crop canopy starts off the same size as the system and gets smaller as the canopy approaches the light. Not to mention the plants grow into an area of high light intensity, perhaps too high, as well as into an area of higher temperature. The only way to get around this is to have the option of moving the plants further away from the central light column, and most vertical systems simply don’t have this functionality.

The Shark Cage also uses rockwool slabs but can also be stacked.

Simon: You need to get multiple factors right for a good vertical grow: a plant variety that doesn’t stretch and go all leggy; the right number of those plants, and the right amount of veg time. Most growers who mess up in vertical simply over-veg their plants.

Ian: Yeah, but all the planning in the world doesn’t make up for a hot spell that causes your plants to stretch. There’s just a lot less margin for error in vertical grows. Whereas in my horizontal garden, I simple lift the lights when I need to, with no reduction in canopy size.

Simon: But what about efficiency! Growing plants 360 degrees around a lamp means every photon has a direct path to a leaf, rather than relying on reflectors (which can reportedly shift spectrums and collect heat) to bounce them.

Ian: This argument for vertical growing is the most common and convincing—you get to make the most out of the light emitted from the whole lamp, without the use of a reflector.

Vertical Grow Species Selection

You HAVE to use plants that grow short and stocky, and have extremely tight internodes. Experience with growing the variety in horizontal gardens is a must. You need to know the ins and outs of every aspect of the plant before attempting to grow it successfully in a vertical garden: Is it particularly susceptible to transplant shock? Does it produce fast, anchoring roots? How much stretch does it put on when triggered to flower? Does it respond well to frequent pruning into a single stem? Can it support its own weight without any plant supports? It is resistant to fungal diseases, particularly botrytis?

Simon: Finally, you’ve managed to say something positive about vertical growing.

Ian: Don’t get too excited. I’m not done yet. With almost all growing systems, the workload is more at the beginning and end of the cycle, but with vertical growing the workload can easily lead to a lack of motivation to get going again. The timing has to be spot on to get the crop cycles right and it’s no easy task. The buddy I helped with the Coliseum took at least a week to turn around a harvested crop into a newly planted one, which obviously ate into the salesman’s promise of six crops a year.

Vertical Grow Environmental Control

Maintaining short, stocky plants in a vertical growing system is a must. Poor control over temperatures in your indoor garden can easily lead to high day-time (lights on) temps and comparatively low night-time temps; the exact opposite of what you want for good short stocky growth. Tight environmental control can help prevent overcrowding. Having a small or zero temperature difference (dif) between day and night will keep plants short.

Simon: Nobody said getting bigger yields was easy Ian, unless you believe the less scrupulous nutrient manufacturers who just want to sell you three different bloom boosters and nineteen bottles of supplements.

Ian: That’s a whole ‘nother story! The only real advantage of vertical growing, as far as I see it, is a saving on floor space. Similar yields can be achieved with horizontal gardens with the same amount of light, and a lot fewer plants. It maybe true that once completely dialed in, the increased lighting efficiency can help increase yields, but certainly not by double as I have seen in some marketing literature for vertical grow systems. I would rather use an extra light and a few extra plants in a horizontal garden, than go vertical.

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DETERMINE YOUR POWER NEEDS

Now that we’ve determined how many amps our devices use, and de-rated that number, we can assess the size of the circuits we will need. Keep in mind, each major appliance group will require its own circuit. In this case, we will need to install the following circuits:

1. The first circuit we need to install will supply 240 volts and 60 amps to a lighting controller that will supply power for ten 1,000 Watt high-pressure sodium lamps and ballasts.

2. The second circuit will be 240 volts and 20 amps, to supply power for a lighting controller that will power six 400W metal halide lamps.

3. The third circuit will be 240 volts and 40 amps, to supply the power for a 5-ton air conditioning system.

4 & 5. The last two circuits will each be 120 volt, 15 amp circuits and will supply power for all of the accessories and controllers.

SURVEY YOUR PANEL

Naturally, you need to make sure that your panel has the capacity to handle your electrical needs. This setup would require at least a 150 Amp panel to run the proposed loads and room to install three 2-pole circuit breakers and two single-pole circuit breakers. A panel survey is the first thing you should do before evaluating the potential of any grow location.

SELECTING THE PROPER WIRE GAUGE

Now that we know what size circuits and breakers we are going to use, we need to determine the size (gauge) of the wire we need to use. Before doing this, let’s quickly understand how many wires you will need for each circuit.

• A 120 volt circuit consists of a single 120 volt line (from either phase), a neutral line, and a ground, for a total of three wires.
• A 240 volt circuit consists of two 120 volt lines (of different phase), a neutral line, and often a ground, for a total of four wires. Some legacy 240V circuits and 240V circuits 20A or less may use a 3-wire configuration, which consists of two 120 volt lines (of different phase), and a neutral line (not a ground), for a total of three wires.

It is vital that you select the proper wire gauge to support and deliver the power to your garden. Using the correct size wire for the amperage requirements of the circuit will allow power to flow to your devices with minimal resistance, and it will prevent the wire from overheating and potentially starting a fire. Always remember that the smaller the wire’s gauge, the larger the wire’s diameter.

Two factors will determine the wire gauge required for any installation. First is the length of the wires, and second is the amount of current the wires need to carry.  The table below provides a guideline for the wire gauge required for your circuits. For medium length wire runs of 75 feet and under, you will want use 400 circular mils per amp. For longer wire runs of 75 to 150 feet, calculate your requirements by using 700 circular mils per amp.

In our example, the distance will be under 75 feet, so we will make our calculations based on 400 Circular Mils per Amp.

Circuit 1: 65 feet of wire for a 60 amp, 240 volt circuit. 60 amps x 400 circular mils per amp = 24,000 circular mils. Referencing the chart reveals you will need to use 6 gauge wire which has 26,244 circular mils. A total of 4 conductors are needed: 2 hots, a ground, and a neutral.

Circuit 2: 65 feet of wire for a 20 amp, 240 volt circuit. 20 amps x 400 circular mils per amp = 8,000 circular mils. Referencing the chart reveals you will need to use at least 10 gauge wire which has 10,384 circular mils.  A total of 4 conductors are needed: 2 hots, a ground, and a neutral.

Circuit 3: 50 feet of wire for a 40 amp, 240 volt circuit. 40 amps x 400 circular mils per amp = 16,000 circular mils. The chart shows that 8 gauge wire would be sufficient, but it is close. When in doubt, always go with a lower gauge. In this case, you should use 6 gauge wire which has 26,244 circular mils.  A total of 4 conductors are needed: 2 hots, a ground, and a neutral.

Circuits 4 & 5: 65 feet of wire for each of two 15 amp, 120 volt circuits. 15 amps x 400 circular mils per amp = 6,000 circular mils. Referencing the chart, you should use 10 gauge wire for this circuit. A total of 3 conductors are needed for each circuit: 1 hot, a ground, and a neutral.

BRINGING CIRCUITS TO THE GARDEN

The photo below shows a 1” diameter EMT conduit originating from the main panel and running along the side of a house. A conduit like this may carry the four wires for a 240 volt, 60 amp circuit to the grow space for a lighting controller.

So far, we’ve determined how many circuits we need to install, the necessary capacity of those circuits, and the wire gauge needed to support the current we’ll be consuming. The next step is getting the wires from the main panel to the place where they need to be – the garden area. This is another step that requires very careful planning. In an installation such as our example, there is no other safe choice than to use Electrical Metallic Conduit, or EMT for short. EMT is metal tubing that comes in various diameters and it shields the wires from weather and any other outside contact. It’s easy to work with, provided you have a few of the right tools.  Don’t use something like Romex that can easily be cut or punctured in a rugged garden environment. This is one of those steps that is going to help you sleep soundly at night. Decide where the termination for each circuit will be and then plan an accessible route for each circuit from your main panel, where the conduit will begin, to the location where the power is needed. You will have to make various bends in the conduit along the way – try to make as direct a route as possible so as to minimize the wire length and minimize conduit bends. Fewer bends will make it easier to pull the wire through later. Connectors are available to mount conduit to the panel enclosure, to splice pieces together and to terminate to almost any type of electrical box. Mount the EMT securely using the companion clips.

This photo shows a circuit directly entering the interior of a residence via a hole drilled straight through the wall.

Now we are getting somewhere. Once the conduit is secured firmly in place, it’s time to start pulling that wire through. Be sure to buy at least 10 feet more wire length than you need for each circuit you are pulling.

When buying wire, buy:

• BLACK for 120 volt phase 1
• RED for 120 volt phase 2
• WHITE for Neutral
• GREEN for Ground

When pulling wire, you’ll also need a fish tape, which is a thin, flat steel wire ribbon on a reel, used specifically for pulling wire through conduit – be sure to get one that will accommodate more than the length you need to pull. Push the fish tape from the termination point of the conduit back through until it reaches the entrance at the panel. Make sure the main is OFF!! Carefully pull about two feet of fish tape out and securely tape the wires you’re about to pull to the fish tape with black electrical tape, in a staggered manner so that it will round bends easier when pulling through the conduit. With one person feeding the wires in at the panel, and the other person reeling-in the fish tape from the other end, carefully pull the wires all the way through from the panel to the room.  Repeat this process for each circuit, until all of the raw wires for each circuit are in their respective conduit and sticking out at each end.

Now, that was easy, wasn’t it? Yeah, I know, not really – it was actually pretty rough. But don’t fret – we’re actually getting closer to that part where you hang the lights, and take some cuttings, etc.

INSTALLING THE CIRCUIT BREAKERS

Now that all of the wiring is in, it’s time to install the individual circuit breakers. If you haven’t done so already, make a trip to your local electrical supply store and get the five circuit breakers that we specified for our five circuits:

1. 60A Double Pole Breaker
2. 20A Double Pole Breaker
3. 40A Double Pole Breaker
4. 15A Single Pole Breaker
5. 15A Single Pole Breaker

This picture shows the main panel with the protective cover removed. Circuit breakers easily snap into place once wires are attached. The neutral wire for each circuit connects to a neutral bus bar and the ground to a ground bus bar.

This photo shows a close-up of where the hot wires connect to the terminal lugs of the breakers. A double pole breaker has two hot wires (red and black). A single pole breaker has one hot wire (either a red or a black). You can spot a double pole breaker by its double thickness and the bar tying the two switches together.

The cover to your main panel should already be off, to expose the bus bars where the breakers actually snap in. Starting with the first circuit, a 240 volt, 60 amp breaker, locate the four 6-gauge wires for the lighting controller circuit where the conduit enters the panel. Trim the wires to length and secure the white wire to the neutral bus bar in the panel. Do the same for the green ground wire – trim to length and secure to an isolated ground bar. Next, trim the red and black wires, strip the ends about 3/8”, and attach them to the terminal lugs on the 60A breaker. Tighten the screws very tightly. Route wires neatly on the side and snap the breaker into its location.

Repeat the breaker installation process meticulously for each set of wires and each circuit breaker. It is critical to connect all neutral wires securely to the neutral bus bar and the ground wires to an isolated grounding bar. Once all of your circuit breakers are installed and all wires are securely attached, double-check everything for accuracy. Make sure all wires are routed without being pinched and make sure breakers are firmly in place. If everything looks good, replace the security cover on the panel, but make sure to leave the main and all of the breakers in the OFF position.

TERMINATING YOUR CIRCUITS

This junction box allows connections to be made from incoming wires to devices or power outlets.

Now we need to terminate each circuit and install our devices. It’s a bit beyond the scope of this article to discuss installing all of your garden components, but we will show how to terminate the first 240 volt, 60 amp circuit and install a lighting controller to power all of your lights – the largest power consumers in your garden. Test with a meter to ensure there is no live current at the termination point before beginning to work on anything.

When the wires from our 60 amp circuit punch through the outside wall to the inside room as in the earlier photo, they will enter a junction box something like the one pictured below. Inside this box, wires are connected together and routed to their destination through additional conduit if necessary. In this case, this junction box ties-in a Powerbox™ lighting controller that powers and controls all of the ballasts and lights in the garden.

INSTALLING A LIGHTING CONTROLLER

We’ve come a very long way and it feels really good to have done things the right way. Now there is one last step for this circuit that is equally as important as all of those steps that brought us this far. We need to install a high-voltage lighting controller to handle the switching of all of the ballasts and lights. A high-voltage lighting controller takes more punishment than any electrical component in your garden, so it’s essential to pick the best quality. Cheap wall timers and inadequate controllers are often the cause of overload, leading to fire. The on and off cycles of heavy amperage loads cause extreme arcing and a lighting controller needs to handle these extreme conditions without being prone to failure.

This photo shows a 60 amp circuit terminating with a Powerbox™ lighting controller, which in turn runs ten 1,000 watt Galaxy digital ballasts. This particular setup also uses 10 Flipbox® switches to double the production of the garden by running two parallel rooms with 10 lamps each, all off of one 60 amp circuit. All equipment is securely mounted to the wall with steel struts.

Secure the lighting controller to the wall firmly in a location near your junction box where the circuit enters the room. Route the cable from the 240 volt lighting controller (e.g. Powerbox™) into the junction box and secure with an EMT-type terminator to the junction box. Splice each of the four wires from the lighting controller main cable to the matching wires from the incoming circuit (black to black, red to red, white to white, green to green). Use insulated lug-type connectors which are available at the electrical supply store. Once the connections have been made, close-up the junction box. You are now ready to test this circuit. Safety first: 1. Make sure the Powerbox breaker is OFF. 2. Go to the main panel and turn ON the 60 amp breaker for this circuit. If the breaker stays on, all is good so far. Go back to the lighting controller and turn the breaker ON. You should now have live power at the lighting controller!!

Although each will be a little different, repeat the circuit termination process for each of the remaining four circuits. None of them will be any more difficult than the one we’ve just done. For the 120 volt circuits, try to locate your outlet boxes close to where they will be used. This means extra conduit, but it’s worth it to avoid using extension cords, which are a garden hazard.

We’ve done so much in so little time. If you are building or upgrading an indoor garden that you hope will provide years of bountiful productivity, you need to build a solid infrastructure. That requires an investment of time and money, but the rewards are huge. It can’t tell you how many setups I’ve seen that have wires duct-taped together and use pie tins as lamp reflectors. Are you kidding me? How can a situation like this not eventually lead to a fire?  And to make matters worse, these are the most under-productive gardens around. Whether your indoor garden is your passion or your business, make the right moves and don’t become another statistic at your local fire department.

Now we’re at that point where it’s time to hang the lights. I don’t think you need me anymore. I’m outta here!  Peace.

P.S. Safety First! Consult with a qualified electrician before doing anything!

WORDS: Jeff Fenley, Powerbox Inc.

Here’s our guide to setting up a basic, conventionally ventilated indoor garden on a budget. We’re going to show the different ventilation requirements for a 2 light and a 6 light grow in the same space.

Big rooms need lots of lights with a high-powered ventilation system whereas small rooms will only need a few lights with a low powered ventilation system. All sounds like simple stuff, doesn’t it? But how do you work out exactly what your room needs? Here’s what you need to consider:

Size

All of the equipment your new indoor garden will need comes down to the size of the room. So, the first thing you need to do is accurately measure it. You will need the length, width and height of the room.
The example shown has the dimensions of:
Length x Width x Height
24ft (7.2m) x 12ft (3.65m) x 8.2ft (2.5m)

Now before we get carried away filling this room with lights and fans, you have to consider the budget and ability of the grower undertaking this new project. A confident and experienced grower may well fill the whole room, but let’s not bite off more than we can chew. First, let’s create a smaller room within the larger room by sectioning off the back portion to give a working room size that is more suited to a beginner.
Length x Width x Height
12ft (3.65m) x 8ft (2.4m) x 8.2ft (2.5m)

You might well be asking, “What are the benefits of sectioning off the room? Why can’t I just hang the lights in the corner?” Well, by creating a room within a room you gain better control of the environment. With the sectioned off area you make the best use of the available light by having walls lined with reflective sheeting – this creates a bright well-lit environment for productive growth.

You can use various materials to section off the room but the better insulated, the better. A well insulated room will immediately lend itself to far easier environmental control.

If you have no interest in building your own indoor garden, or you’re not too confident with your DIY skills then don’t worry, help is at hand. You can purchase purpose-built indoor grow tents – highly recommended for all levels of grower! These come in many sizes, with one bound to suit your requirements, and it makes hanging lights, fans and filters a sinch.

Lighting

Now you know the size of the room you’re working with you can calculate how best to illuminate it. The most widely used light source for indoor gardens is high intensity discharge (HID). They are widely available, competitively priced and produce consistent results. Two types of lamps are able to run in HID systems; High Pressure Sodium (HPS) and Metal Halide (MH).
HID lighting systems are available in many different sizes, but the most commonly used for indoor growing are 1000W, 600W and 400W. Each size light is suitable for a defined amount of floor space:

1000W = 4-5ft (1.2-1.55m)
600W = 4-3.3ft (1.2-1m)
400W = 3.3-2.5ft (1-0.75m)

One thing to bear in mind is that the more powerful the light, the further away from the tops of the plants it needs to be. This means that if you have a low ceiling height, you should consider using lower wattage lights. The example room has an 8.2ft (2.5m) ceiling height so we can use the 1000W lights, as long as the plans don’t get bigger than 5ft (1.5m) which is fine for most plants. Indoor plants want to be short and wide to make the most of the light available. The distance between the light and the canopy that most growers follow are:

1000W = 39-31 inches (100cm-80cm)
600W = 31-24 inches (80-60cm)
400W = 24-16 inches (60-40cm)

Please bear in mind that the above information is for horizontally mounted lamps in normal open or closed reflectors. If you are using parabolic reflectors with vertically mounted lamps or air-cooled reflectors you can allow the light to be closer to the plants as there is less direct radiant heat.

So the floor space available in our room is 12ft (3.65m) x 8ft (2.4m). You could try and squeeze as many lights as possible into this room, but as well as being productive, you want to try and make your room easy and comfort- able to work in. To do this you will need adequate access around your plants to make maintenance and inspections easy. Approximately 2ft (0.66m) around your plants is a good working area. Elderly or disabled growers may opt for considerably more space than this. In our first example we’re using 2 x 1000W lights.

If you want to make life difficult for yourself, you could fit a maximum of 6 x 1000W lights. In order to make this room work you would need to choose a growing system or technique that allows you to move the plants to gain access around the garden. This might be achieved by growing in pots/containers or movable beds.

Ventilation

Ventilation in your indoor garden comprises of two main factors: the removal of hot waste (CO2 depleted) air and the input of fresh cooler air. Hot waste air is removed actively using an inline fan, AKA the extractor fan. Fresh cooler air can either be drawn in passively through vents or pushed in actively using another inline fan AKA the intake fan.
Now we know the size of the room, and the amount if light being used, we can now work out the ventilation requirements. In North America most inline fans are rated in Cubic Feet per Minute (CFM), whereas in Europe they are usually rated in cubic meters per hour (m3/hr).

The Extractor Fan

Firstly, we’ll work out what size extractor fan is needed. There are many ways to work out what size extractor is needed for a particular sized room, some equations are more accurate, others are overly complicated – the following method is very popular and straight forward and has served many growers well.

Required extractor fan size in CFM= Volume of active growing area (ft) x 1.25
Required extractor fan size in m3/hr= (Volume of active growing area (m) x 60) x 1.25

When we say the volume of the active growing area we mean the volume occupied by the lights and plants. To work out the volume simply multiply the length x width x height. In our example with 2 x 1000W lights this is 4ft (1.2m) x 8ft (2.4m) x 8.2ft (2.5m), which gives the volume of the active growing area of 262.4 cubic ft (7.2m3).

Once you have your volume, you need to multiply it by the amount of air changes needed per unit of time. For the majority of indoor gardens without AC or supplementary Co2, the rule of thumb is one air change per minute. For the CFM equation there is no need to multiply it as we already have the total volume in cubic ft which is needed to be changed every minute. For m3/hr equation we need to multiply the volume by 60 to step it up to the amount of air changes needed per hour.

Lastly, when using a carbon filter attached to the extractor fan we expect a drop in fan efficiency of approximately 25%. This figure is not fixed; it depends on the make and age of the filter and the length and course of ducting between the fan and filter and many more interesting factors that we won’t bore you with here. To step up this efficiency drop of 25% simply multiply by 1.25.

If we run this equation through our example indoor garden it gives us;
Required Fan size (CFM) = (Volume of Active Growing Area) x 1.25
(4 x 8 x 8.2) x 1.25 = 328 CFM

Required Fan size (m3/hr) = (Volume of Active Growing Area x 60) x 1.25
(1.2 x 2.4 x 2.5) x 60 = 432.
432 x 1.25 = 540 m3/hr

This final figure is the minimum size extractor needed. If the garden is in a very well insulted location such as a basement using this figure should be fine. If the garden is located in a very sun-exposed location such as an upstairs bedroom or attic then the extractor size may need to be increased by approximately 25%. More often than not, you will have to match your required extractor size to the nearest size avail- able. In this instance the nearest widely available inline fan size is a 6” (150mm) 390CFM (660 m3/hr) extractor.

Interestingly, if we work though the equation for the same room with 6 x 1000W lights it will give very a different answer;

Required Fan size (CFM) =  (Room volume) x 1.25
(12 x 8 x 8.2) x 1.25 = 984 CFM

Required Fan size (m3/hr) =  (Room volume x 60) x 1.25
(3.65 x 2.4 x 2.5) x 60 = 1314
1314 x 1.25 = 1643 m3/hr

In this indoor garden the nearest widely available fan size available is a 12” (315mm) 1000CFM (1700 m3/hr) extractor.

Oversized Fans

Many growers think ‘bigger is better’ when it comes to extraction but this is not always the case. By extracting air from the garden you’re removing the heat, but you’re also removing the hu- midity. This means that an oversized ex- tractor fan can often cause low relative humidity, which will create an onslaught of negative effects that will lead to poor plant growth.

‘Summer sized fans’ are also not always the answer to a warm indoor garden. There comes a point where it doesn’t matter how much air your extracting, if your incoming air is warm your room will stay warm. If you can’t keep the heat down and you’re changing the air in your garden more than three times a minute, you need to consider installing air conditioning or using air-cooled or water-cooled grow lights.

Fresh Air

As mentioned earlier, we need to get fresh air into the garden. This can be done using two methods:

1. By making passive vents (basically holes) through which fresh air can be drawn in.
2. By installing active inline fans that push fresh air into the garden.

When using passive vents you have to ensure there is adequate fresh air outside the growing area. It’s no good if you’re pulling in stale or warm air. This means you may need to have a window open so fresh air can be drawn in from outside and into the indoor garden. As a rule of thumb, the passive vents should be two to three times the size of the surface area of the extractor fan outlet. This means if the extractor has a 6” (150mm) spigot size, the garden will need 2-3 x 6” holes or rectangular vents with and equal surface area. When installing passive vents always have the extractor fan at the opposite end of the room. It’s better to have oversized passive vents than undersized. If the vents are too small, the extractor fan will struggle to pull in sufficient quantities of fresh air.

Indoor gardens with active intake fans often run more efficiently than those with passive vents. By pushing in fresh air you not putting as much strain on the extractor fan and you also get to choose where to pull the fresh air from. During the cooler winter months its best practice not to pump in very cold air, so a lot of growers pull slightly warmer air from inside their home. If it’s a room you spend time in, like your bedroom or living room, it will also have the added benefit of the air being slightly higher in Co2. During the summer months its best to pull fresh cooler air in directly from outside as air from inside you house is likely to be warmer. Whenever you pull air straight from outside it’s best to use an intake filter or ‘bug screen’ to limit the possibility of sucking in pests.
The golden rule when installing an intake fan is to make sure you’re blowing in less air than is being removed by the extractor. This creates a ‘negative pressure’ and ensures that all the air exits through the carbon filter. If you input more air than the extractor can remove the air will start to build up and cause a ‘positive pressure’ forcing untreated air out of the garden.
When selecting an intake fan it should have a maximum capacity that is 10-20% lower than the actual output of the extractor. This will maintain adequate negative pressure while not putting too much strain on the extractor and intake fans.
To work out the intake fan size we will need to take the extractor fan size and apply an estimated reduction for the carbon filter- 25%. If our target for the intake fan is 15% less air than the exhaust we need to multiply the reduced output by 0.85. Below is a work through of how to size up the intake fan for both or the example rooms.

2 light room:

Extractor size – 390 CFM (660 m3/hr)
Estimated extractor power with carbon filter – 390 x 0.75 = 292.5
Reduction to ensure negative pressure = 292.5 x 0.85 = Intake Fan Size 249 CFM (420 m3/hr)

6 light room:

Extractor size – 1000 CFM (1700 m3/hr)
Estimated extractor power with carbon filter – 1000 x 0.75 = 750
Reduction to ensure negative pressure = 750 x 0.85 = Intake Fan Size 638 CFM (1084 m3/hr)

When installing the intake fan, make sure the extractor is at the opposite end of the garden. It’s a good idea to split the intake air with a solid ‘T’ or ‘Y’ piece so that the cooler fresh air is distributed evenly. Using air socks or longer lengths of ducting with holes in is a good way of evenly distributing the incoming fresh air.
One last factor to consider is that inline fans are better at pushing than pulling air through ducting. This means than when positioning your intake fan, it’s better to place it nearer the source of fresh air and push it towards the indoor garden. To make the air reach the garden efficiently, make sure the duct runs are as smooth and straight as possible.

Air Movement

Moving the air within the garden is of utmost importance. A light breeze moving air over the plants’ leaves refreshes the CO2 depleted air, gets rid of heat and humidity and encourages transpiration. The area of an indoor garden where most unwanted heat will accumulate is between the lights and the canopy, so it’s absolutely crucial that this air is removed to avoid heat build up. To achieve good air movement between the lights and the canopy you can install fixed or oscillating air circulation fans. These can be wall mounted or floor standing and should be powerful enough to mix the air well, while not causing the plants to be blown too vigorously. You want to move the air, not your plants! If you point strong air circulators straight at your plants the air will move past the leaves so quickly that it will strip away the humidity surrounding the leaf and encourage rapid transpiration. This leads to the leaves losing water rapidly and can cause them to appear burnt at the edges crispy to touch; this is known as ‘wind burn’. If you need to enhance the air movement around your plants, it’s a good idea to point air circulators towards walls rather than directly at the plants to mix the air adequately while not causing the plants to be flapping around in turbulent wind.

Equipment location

To avoid unnecessary heat transfer, any equipment that generates heat should to be stored outside the garden. Most notably, the power packs (aka ballasts) that can get quite warm need to be situated outside the garden on a shelf or any non flammable surface. Having them outside the room also is best practice for electrical safety as they won’t be operating in a warm and humid environment and will not have risks of stray foliar sprays landing on them or accidental splashes of nutrient solution.
Nutrient solution will also benefit from staying outside the garden. Your reservoir will quickly heat up under the direct light from your grow lights so its best practice to locate your reservoir outside the garden.

Any liquid nutrients and additives should not be stored in hot or cold environments. It’s best to consult the packaging and see what the best environment is for your products but most appreciate a constant moderate temperature. This should again be outside your garden.

Summary

Following the above principles you can construct your- self a great, budget indoor garden, suited around you, while creating the ideal environment for your plants. All you need to do after this is choose a method to grow your plants whether it’s growing passively in plant pots, or using an active hydroponics system such as an Ebb and Flow, Drip, or NFT – all will flourish in your well planned indoor garden.

NEXT TIME:
We will be looking at selecting the best growing system to suit the needs of you and your garden and using fan speed and environmental controllers.

Have you ever been given this odd-sounding advice? Even when we are encouraged to try and understand how plants work, our inherent tendency to personify the natural world is inescapable. Growers often like to draw parallels between humans and plants, after all, there’s no doubt that plants are marvelous, highly specialized and well-adapted organisms. You might even go as far to say they are “intelligent.” But let’s be honest here. Plants are totally different from us, especially in the way they react and respond to their environment. However, if we can get our heads around the world from a plant’s perspective, we become what is commonly referred to as “green-fingered.” We become … better growers.

Have you ever wondered how plants “feel” humidity? An understanding of what humidity is, what it means to plants, and how you can manage it in your indoor garden will help you and your plants stay happy all year round.
The humidity of the air is basically the amount of water in the air. Water can only truly stay in the air when it is the invisible gas – water vapor. Small droplets of water in air, such as fog or mist, are not water vapor; they are simply larger particles of water temporarily suspended in the air that are ready to be turned into water vapor by evaporation.

Temperature plays an important role when it comes to humidity. The warmer the air, the more water vapor it can hold. This means the maximum amount of water that air can hold is directly related to the temperature of the air. As the amount of water air can hold constantly changes with temperature it is difficult to pin an absolute or fixed amount of water that can be held by air. So what’s the best way to quantify humidity if the goal posts are changing all the time? The answer is something called Relative Humidity (RH) – this is a measure in terms of percentage, of the water vapor in the air compared to the total amount of water vapor that the air could potentially hold at a given temperature.

Why is RH so important?

As growers we measure the RH of our gardens using digital or analogue hygrometers. These readings are very important because RH has a direct effect on the plant’s ability to transpire and therefore grow. Generally, plants do not like to lose lots of water through transpiration. Plants have some degree of control of their rate of transpiration through management of their stomata but the general rule is the drier the air, the more plants will transpire.
Now let’s move on to the idea of “pressure” – this is an important concept to grasp when it comes to understanding a plant’s response to humidity. All gasses in the air exert a pressure. The more water vapor in the air the greater the vapor pressure. This means that in high RH conditions there is a greater vapor pressure being exerted on plants than in low RH conditions. High vapor pressure can be thought of as a force in the air pushing on the plants from all directions. This pressure is exerted onto the leaves by the high concentration of water vapor in the air making it harder for the plant to ‘push back’ by losing water into the air by transpiration. This is why with high RH plants transpire less. Conversely, in environments with low RH, only a small amount of pressure is exerted on the plants’ leaves, making it easy for them to lose water into the air.

What is Vapor Pressure Deficit (VPD)?

VPD can be defined as the difference (or deficit) between the pressure exerted by water vapor that could be held in saturated air (100% RH) and the pressure exerted by the water vapor that is actually held in the air being measured.
The VPD is currently regarded of how plants really ‘feel’ and react to the humidity in the growing environment. From a plant’s perspective the VPD is the difference between the vapor pressure inside the leaf compared to the vapor pressure of the air. If we look at it with an RH hat on; the water in the leaf and the water and air mixture leaving the stomata is (more often than not) completely saturated -100% RH. If the air outside the leaf is less than 100% RH there is potential for water vapor to enter the air because gasses and liquids like to move from areas of high concentration (in this example the leaf) into areas of lower concentration (the air). So, in terms of growing plants, the VPD can be thought of as the shortage of vapor pressure in the air compared to within the leaf itself.

Another way of thinking about VPD is the atmospheric demand for water or the ‘drying power’ of the air. VPD is usually measured in pressure units, most commonly millibars or kilopascals, and is essentially a combination of temperature and relative humidity in a single value. VPD values run in the opposite way to RH vales, so when RH is high VPD is low. The higher the VPD value, the greater the potential the air has for sucking moisture out of the plant.
As mentioned above, VPD provides a more accurate picture of how plants feel their environment in relation to temperature and humidity which gives us growers a better platform for environmental control. The only problem with VPD is it’s difficult to determine accurately because you need to know the leaf temperature. This is quite a complex issue as leaf temperature can vary from leaf to leaf depending on many factors such as if a leaf is in direct light, partial shade or full shade. The most practical approach that most environmental control companies use to assess VPD is to take measurements of air temperature within the crop canopy. For humidity control purposes it’s not necessary to measure the actual leaf VPD to within strict guidelines, what we want is to gain insight into is how the current temperature and humidity surrounding the crop is affecting the plants. A well positioned sensor measuring the air temperature and humidity close to, or just below, the crop canopy is adequate for providing a good indication of actual leaf conditions.

Managing Humidity

Managing the humidity in your indoor garden is essential to keep plants happy and transpiring at a healthy rate. Transpiration is very important for healthy plant growth because the evaporation of water vapor from the leaf into the air actively cools the leaf tissue. The temperature of a healthy transpiring leaf can be up to 2-6°C lower than a non-transpiring leaf, this may seem like a big temperature difference but to put it into perspective around 90% of a healthy plant’s water uptake is transpired while only around 10% is used for growth. This shows just how important it is to try and control your plants environment to encourage healthy transpiration and therefore healthy growth.
So what should you aim to keep your humidity at? Many growers say a RH of 70% is good for vegetative growth and 50% is good for generative (fruiting /flowering) growth. This advice can be followed with some degree of success but it’s not the whole story as it fails to take into account the air temperature.

Humidification systems to increase RH.

Table 1 shows the VPD in millibars at various air temperatures and relative humidity. Most cultivated plants grow well at VPDs between 8 and 10, so this is the green shaded area. Please note that the ideal VPD range varies for different types of plants and the stage of growth. The blue shaded are on the right indicates humidification is needed where the red shaded area on the left indicates dehumidification is needed.

By looking at this example we can see that at 70% RH the temperate should be between 72-79°F (22-26°C) to maintain healthy VPDs. If your growing environment runs on the warm side during summer, like many indoor growers, a RH of 75% should be maintained for temperatures between 79-84°F (26-29°C.)

The problem with running a high relative humidity when growing indoors it that fungal diseases can become an issue and carbon filters become less effective. It is commonly stated that above 60% RH the absorption efficiency drops and above 85% most carbon filters will stop working altogether. For this reason it is good practice to run your RH between 60-70% with the upper temperature limit depending on your crop’s ideal VPD range, in the example it would be 64-79°F (18-26°C.)

The table also shows that if your temperature is above 72°F (22°C), 50% RH becomes critically low and should generally be avoided to minimize plant stress.
Please understand that by presenting this information we do not want you to go to your indoor gardens and run your growing environment to within strict VPD values. What’s important to take from this is that VPD can help you provide a better indication of how much moisture the air wants to pull from your plants than RH can.
If you want to work out for yourself the VPD of your plants leaves you can follow the steps below:

1. Measure the leaf temperature and look up the vapor pressure at 100% RH on table 2 below.
2. Measure the air temperature and relative humidity and look up the nearest vapor pressure figure on table 2.
3. Subtract the air vapor pressure from the leaf vapor pressure

Example:
Leaf Temperature = 24°C (100% RH)     Leaf VP: 29.8
Air Temperature = 25°C @ 60% RH     Air VP:     19.0
VPD=     10.8

Humidity’s Effect on Plants

Plants cope with changing humidity by adjusting the stomata on the leaves. Stomata open wider as VPD decreases (high RH) and they begin to close as VPD increases (low RH). Stomata begin to close in response to low RH to prevent excessive water loss and eventually wilting but this closure also affects the rate of photosynthesis because CO2 is absorbed through the stomata openings. Consistently low RH will often cause very slow growth or even stunting. Humidity therefore indirectly affects the rate of photosynthesis so at higher humidity levels the stomata are open allowing co2 to be absorbed.

Leaf roll on Thai basil- Localized humidity stress causes by the lights being too close.

When humidity gets too low plants will really struggle to grow. In response to high VPD plants will try to stop the excessive water loss from their leaves by trying to avoid light hitting the surface of the leaf. They do this by rolling the leaf inwards from the margins to form tube like structures in an attempt to expose less of the leaf surface to the light, as shown in the photo.

For most plants, growth tends to be improved at high RH but excessive humidity can also encourage some unfavorable growth attributes. Low VPD causes low transpiration which limits the transport of minerals, particularly calcium as it moves in the transpiration stream of the plant – the xylem.  If VPD is very low (95-100% RH) and the plants are unable to transpire any water into the air, pressure within the plant starts to build up. When this is coupled with a wet root zone, which creates high root pressure, it combines to create excessive pressure within the plant which can lead to water being forced out of leaves at their edges in a process called guttation. Some plants have modified stomata at their leaf edges called hydathodes which are specially adapted to allow guttation to occur. Guttation can be spotted when the edges of leaves have small water droplets on, most evident in early morning or just after the lights have come on. If you see leaves that appear burnt at the edges or have white crystalline circular deposits at the edges it could be evidence that guttation has occurred.

Guttation on tomato plants caused by high RH and wet coco coir.

Powdery Mildew from poor humidity control.

Most growers are well aware that with high humidity comes and increased risk of fungal diseases. Water droplets can form on leaves when water vapor condenses out of the air as temperature drops, providing the perfect breeding ground for diseases like botrytis and powdery mildew. If humidity remains high it further promotes the growth of fungal diseases. The water droplet exuded through guttation also creates the perfect environment for fungal spores to germinate inviting disease to take hold.

Quick reference chart:

So hopefully now you are not just ‘thinking like a plant’ – you’re ‘feeling it’ too!

Next time, part two of Plantworks will be looking at foliar spraying and how plants absorb nutrients into their leaves.

1. Insulation

The better your indoor garden is insulated, the easier it will be to grow in it. Many indoor gardens suffer from excessive heat problems, especially during the summer months when ambient temperatures are considerably warmer. High temperatures can slow plant metabolism and stress your plants causing them to respond in unfavorable ways. This isn’t just a euphemism for death either. Many culinary herbs and lettuces will ‘bolt’ into premature flower and seed production if they are forced to endure prolonged high temperatures. Similarly, if nighttime temperatures drop too low this invariably stunts growth and bloom. Cold, poorly insulated rooms cause very slow growth, poor water and nutrient uptake, and low temperatures can cause further undesired changes in your plants – e.g. chili peppers will fruit prematurely if nighttime temperatures drop below 65°F (18°C). So remember, the better a potential grow space is insulated, the greater the “base level” of protection from extremes in ambient temperature and the less money and effort you will have to invest into controlling temperatures in your indoor garden. Is it really worth all the energy, money and time investing in a state-of-the-art cooling system to chill your grow lights in a ramshackle loft apartment in Los Angeles, or will it simply be cheaper and easier in the long-run just to move to somewhere more suitable? Now’s the time to ask yourself these questions!
Take a moment to think about the general characteristics of your house or apartment. What is it made of? Wood, stone, brick, concrete? How thick are the walls? What type of insulation has been used? Not sure? Ask yourself these questions: Does your home already get too hot in the summer, and is it a pain to keep warm during the winter? In either case – not a good sign! What about your indoor garden’s location within your home? Is it in a room at the top of the house that has an external wall facing the sun all day? Or is it cool and shady? Hopefully you’ll be nodding at the latter.
Insulation is measured by its R value. The higher the R value, the more effective the insulation. Some of the best insulation materials are:

• Blown in Cellulose Insulation – R3.70 per inch
• Fiberglass Insulation – R3.14 per inch
• Expanded Polystyrene – R4.00 per inch

Many growers report their greatest successes from gardens located in a cellar or basement. And there is a good reason for this – the amazing insulation qualities of the earth! So whether you are storing wine or growing food to accompany it, a basement can be ideal. (Just don’t do both at the same time!) Basements can be subject to high humidity, so you may also need to invest in a dehumdifier. Their subterranean location can make getting rid of spent nutrient solution more tricky than usual.

2. Ceiling Height

Look up. What do you see? Hopefully it’s a ceiling high above you, well out of reach. 8 ft ceilings are okay. 10 ft or more is a godsend for any indoor gardener – that extra air volume makes your life so much easier, believe. Not only do you have more height to grow climbing varieties of tomato, peas and beans but, once again, you will find your temperatures and CO2 levels far easier to maintain and control. Additional ceiling clearance means that you also have the option of raising the height of your grow trays so that your garden is easier to work in, with the additional benefit of making drainage / nutrient return easier to manage using plain old fashioned gravity alone.

3. Water

Your plants want a lot of things – some of them desirable, some of them essential. One thing they can’t possibly go without is water! Prior research into the water quality of the area will be useful. Generally, the softer the water the easier it is to grow with. Hard water can still be used to produce productive crops but a lot of growers now use RO machines to remove the carbonates and other contaminants. Indoor gardeners commonly use a large container such as a rain collection barrel to mix and store their nutrient solutions – often referred to as a reservoir or ‘res.’ Ideally this should be kept in an adjacent room so that your nutrient solution is not subject to the temperature changes in the growing area itself. Think about where you are going to store your nutrient solution and its location relative to your nearest water source. Running hoses across landings or up and down stairs is a pain and invariably leads to leaks and spillages. I’ve lost count of the amount of times a hose end has flopped itself out of a res, spewing water all over the floor. It’s a nightmare scenario! Filling up your res is a regular chore, so make your life as easy as possible with sensible planning and, ideally, a dedicated tap right above it. The less hose pipe in your life, the better! (My wife hates seeing hose pipe running from room to room!)

4. Drainage

It’s not just about getting water into your indoor garden. What about getting it out? Is there an easy way to drain your spent nutrient solution? Once again, it’s all about making life easy for yourselves! Most growers use a submersible pump and hose to drain their reservoirs. Some growers recycle their spent nutrient solution by using it on their outdoor gardens too.

5. Ventilation / Windows

Unless you are growing in a sealed room with AC and CO2 supplementation, you are going to need to install some sort of ventilation in order to keep on top of temperature, humidity and CO2 levels in your indoor garden. Many novice growers grossly underestimate their ventilation requirements. Remember, all that hot, CO2-depleted air needs to go somewhere. And then it needs to be replaced with cool, clean, fresh air of course! Simply pumping air out of your grow tent back, for example, into the same room it’s situated in does not count as adequate ventilation. We need to transport the old air well away, and keep the fresh air … well fresh!
Think of your ventilation in terms of input and output. In order to maximize your control over your indoor garden’s environment you should always spec the size of your output (aka extraction) inline fans bigger than your input. More air being pumped out than being pumped in creates a ‘negative pressure’ which ensures zero air and odor leaks and also increases the efficiency of your input fans. If you are using carbon filters with your input or output fans, remember to take into account their diminishing effect on their respective fan – often a 25% reduction factor is used but depending on the make and age of the filter it could be anywhere between a 10 – 30% reduction.
Extraction has the most positive effect on reducing temperature when it is removing air from the top of a room – as hot air rises. Ideally it should be vented out of the property to the outside world. As far as intakes are concerned, be aware of where you are taking your air from. Drawing ice-cold air direct from sub-zero temperatures outdoors and blowing it directly on your plants is not clever. It’s a far better option to draw air from a cool room in your home instead. Be sure to use a bug screen on all air intakes. Yes, you will have to spec up your fan by 10-30% to counter the increased air resistance, but at least you won’t be drawing bugs, mold spores and pollens into your indoor garden!

Size and Accessibility

Remember, you need space to work and get around in your garden. Ideally you should be able to access your growing area from all sides, allowing you to inspect all your plants with the same level of care and precision. Overfilling your garden, however tempting, will quickly turn maintenance into an onerous, back breaking exercise. Remember, your hobby should be a pleasure, and not a chore!

Pest Protection

All carpet should be removed from any space where you are planning to grow as it can harbor no end of pests and pathogens. If removing the carpet is not an option, you can lay down protective plastic sheeting. Remember, your indoor garden should be as easy as possible to keep squeaky clean. A laminate floor that is easy to mop is ideal. Air intakes should use a bug screen so that you don’t inadvertently suck bugs into your garden.

Next issue: Electrical Safety in your indoor garden – so important, we need to tackle this subject on its own!

There are a lot of CO2 generators on the market, varying by capacity. Connecting either a propane or natural gas line, a generator burns gas to produce CO2. When the burner is on, CO2 is generated. When it’s off, not.

Controlling this with an electronic CO2 controller will avoid wasting gas and create the exact environment of your choice.

Alternatives to using a gas-burning CO2 generator include the yeast/sugar soda bottle method (very imprecise) or a CO2 tank with a CO2 regulator.

Hydro Innovations’ MiniGEN is a compact CO2 generator and comes in at 6″x7″x10″. It’s small and adorable. Like Pikachu, small packages can generate powerful results.

Included accessories

– AC adapter
– 2 small screw hooks to screw into the top of the MiniGEN (for hanging)
– 2 worm-gear hose clamps for the water-cooling hose bibs
– 2 mounting screws for mounting the unit against a wall or wooden support
– 12-foot gas line with regulator for your propane tank

Setup & Installation

– Connect the included gas hose to the MiniGEN and a propane tank.

– Either hang the MiniGEN via its included screw hooks (good metal ones, too!) or flush-mount the unit against a wall. I opted to use ratcheting rope hooks with the screw hooks, but standard light chains would be fine.

– Plug the AC adapter into the MiniGEN and then into your CO2 controller.

– Slide the water hoses onto the hose bibs. The water hoses slide easily onto the front hose bibs for the MiniGEN. Cinch down the connections with the included worm-gear clamps and you’re good to go. I only wish that all of Hydro Innovations’ gear used these hose bibs. Easy on and easy off.

– For added measure and because I am paranoid, I teflon-taped the MiniGEN water hose bibs. As a former Boy Scout, I believe that added safety breeds security. No exception here—albeit the directions specifically state that these measures are not required.

Operation

Once everything is connected, your CO2 controller takes care of the MiniGEN.

The MiniGEN does have an on/off switch. Prior to walking away from your installation, ensure that you turn this on. The switch proves very handy when working around in your grow room. No need to waste CO2 with your grow chamber open—flip the switch to ‘Off.’

One exception to using a CO2 controller. If you are using CO2 as a natural pest-killer (around 10,000 PPM), you won’t use a CO2 controller. OR, you’ll use one that allows you to specify 10,000 PPM as an acceptable level.

Not only will this eradicate all pests in your grow room, you may eradicate yourself if not careful. Show extreme prudence if you attempt this sort of CO2 application.

Performance

Once connected, the MiniGEN takes a few clicks (of the electronic ignitor) to light the propane. I watched the CO2 controller. Two minutes later, the indicator crept from 500 PPM to 1500 PPM CO2 and turned off the burner. The MiniGEN’s burner generates 1.5 cubic feet/hr of CO2.

My grow chamber is 4′ wide, 3′ deep, 7′ tall. I hung the MiniGEN slightly above my light reflector and laid the CO2 controller slightly beneath the plant bases—approximately 3 feet between the two. This way, I ensured that at least 1500 PPM CO2 flowed across all levels of the plant tops.

Heat

A common issue with CO2 generators is heat. Pure and simple, fire is burning the propane to generate your CO2. Fire = heat. What to do with it?

The good folks over at Hydro Innovations solve that problem with all of their CO2 generators by water-cooling the units. Using a water chiller and pump with the MiniGEN, my grow room sees no added heat—at all.

If you’re running the MiniGEN without the water cooling (which you can do), you will need to add some sort of environmental cooling (ala conventional air conditioning or via a Hydro Innovations IceBox setup).

Safety

For being such a small unit, the MiniGEN incorporates two cool safety features:

– The electronic ignitor turns on only when CO2 is to be generated. No pilot light. Not only does this eliminate an unnecessary active fire in your grow chamber, but it conserves gas.

– An anti-tip sensor will not allow the ignitor to trigger if the unit is not level. If the unforeseen happens and the MiniGEN falls down or tilts, the unit will not fire.

How to make it better?

For once, I’m stumped.

The only suggestion that I can offer is a visual indicator of propane flow. I have not run out of propane yet. When I do, the only indicator will be the constant clicking of the MiniGEN’s ignitor. If I’m on an extended trip, this might last several days.

A visual indicator of either the flame or the gas (flowing/not flowing) might work well. However, on the MiniGEN itself, this would be less than ideal because you would need to open your grow room to see the indicator. Instead, the included 12′ propane hose should be substituted for one with a flow indicator on the tank side.

Other than that, this is a simple, perfect little beast.

Conclusion

If you have a grow room on the medium to small size (10′ x 10′ x 10′ or smaller) or otherwise don’t need super-fast CO2 flow, the MiniGEN is YOUR CO2 generator.

Simple. Cool. Efficient. Safe. Enough said.

Happy Gardening,

Curtis

Unless you want to sit in front of your plants and breathe sweet nothings onto your plants, you need to artificially add CO2.  Indoor gardens love a carbon dioxide concentration of 1500 PPM.

Under the rarest of occurrences, you can boost that to 10,000 PPM for 15 minutes to kill all crawling critters molesting your plants.  Be careful with this application and know thoroughly what you are doing.  Such high CO2 concentrations will kill you.

There are currently two ways to add CO2 to an environment:
1)  Get a CO2 tank and CO2 regulator to maintain a consistent PPM.
2)  Use a CO2 generator to burn propane and separate the CO2 from the propane with the assistance of an electric monitor or regulator to control the on/off of the CO2 generator.

Hydro Innovations’ CO2 Monitor fits the bill.

The CO2 Monitor is a perfect example of KISS (Keep It Simple, Stupid).  Plug in the monitor, connect your choice of CO2 generators, wait a few seconds for the monitor to boot up, and you’re ready to roll.  I would recommend placing the monitor at the opposite corner from your generator to ensure a minimum application of CO2 to all corners of your grow room.

The monitor defaults to maintaining the environment at 1500 PPM of CO2.  It starts your CO2 generator at 1300 PPM and shuts it off at 1500 PPM.
Here we have what’s included in the package.
– 1 A/C adapter for the CO2 Monitor itself
– CO2 Monitor with power cable for your CO2 generator

You can mount the monitor to the wall for easy reading.  For myself, I set the CO2 Monitor down in a corner of my grow room, opposite my CO2 generator.

I have the CO2 Monitor connected to the same timer as my grow light.  Plants don’t really require much CO2 during lights-out, so any generated with the lights out is a waste.

Fancier CO2 Monitors (read:  more expensive) can fine-tune the PPMs in your grow room.  Really, you don’t have to.  KISS is good for you.  On at 1300.  Off at 1500.  Easy.

My only suggestion for improvement to the monitor is to incorporate its own power supply into the plug, which also powers the generator.  However, this would require some tricky electrical engineering to power the monitor and not power your CO2 generator. This would eliminate the extra AC cable.

Simple partner for your CO2 generator. Get it. Connect it. And forget about it.

Happy Gardening!
Curtis

Please note: blog posts are the opinions of independent growers, and do not necessarily reflect the opinions of Urban Garden Magazine or its affiliates.

Day 01 Day 08 The roots have grown down to the nutrient solution, and all is going well.Plants have needs, but as long as those needs are being met, they are astoundingly flexible on exactly how those needs are met.

In this example, the plant is supplied with crocheted netting for the rooting media and support, and with air from the exposed roots and the aerated nutrient solution. The plant receives water and nutrition from the solution, and normal lighting from above. The exact same requirements a soil plant needs: those needs just get met in different ways depending on how you choose to garden. Day 09
Day 11
Peace, love, and puka shells,

Grubbycup ]]> http://urbangardenmagazine.com/2010/02/crochet-hydroponics-part-3/feed/ 0 http://urbangardenmagazine.com/2010/02/is-water-the-best-growing-medium-on-the-planet/ http://urbangardenmagazine.com/2010/02/is-water-the-best-growing-medium-on-the-planet/#comments Tue, 16 Feb 2010 17:02:06 +0000 Urban Garden Magazine http://urbangardenmagazine.com/?p=2837 Could H2O be the best growing medium on the planet?

Daniel Wilson invites us to rethink what gardening in earth vs. gardening in water really means to the sustainability of indoor gardening.

Allow me to paint you a picture…

It’s a beautiful day in Anywhere, USA. It’s 10:30 a.m. and somebody just woke up, had their herbal tea and is now ready to tackle a long day of transplanting young plants into 7 gallon containers of Sri Lankan coco. They hop into their biodiesel powered 4×4 and head straight for the local grow store to pick up the pallet of coco it’s gonna take to fill those 120 containers. After dropping a cool $1,500 for the medium and another $250 for containers, they load up their rig and jump back on the 101 and it’s off to work. Sound like anybody you know?

There’s obviously a fair amount of energy someone’s just expended and they haven’t even started “work” yet. It’s pretty obvious this is a labor intensive method, but it’s well worth it because they’re growing organically, right? Oh … they’re using synthetic coco fertilizers, run drain-to-waste? But don’t they live in the woods? What happens to the run-off? Thank goodness nutrients come in 5 gallon containers because we’re going to be getting through a whole lotta nutes using the drain-to-waste method, right? Okay okay … I’ll quit this righteous talk. But let’s take a minute to ask ourselves a far more relevant question:

Q: Is it really sustainable to continue shipping millions of pounds of growth media all over the planet?

The current practice of bagging soils and shipping it indiscriminately around the globe has helped propel container soil/coco growing to its current popularity in the indoor grow scene. Though this is, without a doubt, a productive technique, it certainly makes the business of growing in earth a very petroleumintensive practice. Most of the organic growers I talk to take great pride in the natural grow medium they use and feel it’s the ecologically appropriate way to garden … as nature intended. Very few growers consider the great costs incurred by transporting that bag of earth conveniently to their local garden shop. The trucking of this relatively abundant resource (earth) has become quite commonplace in both greenhouse and year-round gardening circles. We rarely give a second thought to the amount of energy the bag of earth we depend upon so much represents. In fact, many growers are so confident in the sanity of these perpetual shipping practices that they will buy brand new bags of earth for their next cycle of plants to follow this round. Alas, very few would consider the idea of composting their used grow medium to be used to generate future harvests.

That being said, we need to consider what would happen if the shipping of soils for thousands of miles just becomes impossible … due to regulations on shipping or even a reluctance of a region to want to give up its precious carbon source, perhaps seeing it a better idea to keep it local and grow food in it as opposed to trading it for money. I know, I know, some of this might seem pretty far out and unlikely but it’s these awkward questions that lead us into discussions which begin to propagate solutions for the future. The critical thinking necessary to tackle issues before they become an “issue” is what we need to strive for as a garden and farm-based civilization. Past populations both benefitted and suffered from the methods they preached and practiced. It’s only in hindsight that clarity begins to develop and we are able to steer a course for the better.

So this leads me to our next Q & A.

Q: What is the most sustainable grow medium for the future of indoor and greenhouse cultivation?

For this question there is no simple answer.

1) The renewability of coir fiber is promising, but unless coir is a local product we are still faced with the shipping issues.

2) Naturally derived soils are another obvious option but, as with coir, unless we can solve the shipping dilemma it too falls short with regard to its practicality over time.

3) Stone wool (aka rock wool) products are a mainstay of commercial growers and are a fairly sustainable option – but it takes intense amounts of energy and large factories to process into forms well-suited for plant cultivation. And there’s still the matter of shipping, as far as from Holland to California at times: yikes.

4) Regional soils offer a pretty attractive option as we could build soils from an area’s most naturally occurring resources. This might mean West Coast Soils, East Coast Soils, Deep South Soils … you get the gist. This would make for minimal shipping, and it just makes sense.

5) Expanded clay pellets are another option with a light and dark side. Though made out of naturally occurring inputs, it (like stone wool) is energy intensive to make and costly to ship. More often than not it’s coming all the way from Germany!

6) Local water sources all over the planet offer a reusable and renewable way of growing healthy food, fiber and medicine. It’s possible to pump water vertically from indigenous terrestrial aquifers, or when available, benefit from naturally occurring snow melt driven by gravity.

Is it really possible that water could be considered a viable alternative to growing crops in a conventional substrate? What about plant nutrition? This leads us to our next question …

Q: Besides Aquaponics, don’t most high performance water culture applications rely on inorganic nutrients to work most productively?

Hydroponic applications use mineral salts to provide plants with the nutrition they require to grow and bloom. Most hyper-oxygenated water culture methods tend to greatly increase the efficiency of nutrient uptake in the plants’ root zone. This, in turn, maximizes these naturally occurring earth elements by offering them to plants in their most available forms. Typically you can run your nutrient solution at 40%-70% strength when compared to regular application recommendations for any given nutrient. Combine this with the closed loop nature of the majority of water culture applications and you are feeding your crops and also managing our planet’s most precious resource in a responsible, efficient manner.

Q: Isn’t that still using petroleum-intensive inputs to grow plants? So what’s the difference between this and using petroleum to ship soils?

Most notably, the difference is the reduced emissions from the avoidance of burning fossil fuels to ship transcontinental distances. Besides, this efficient nutrient uptake and constant recirculation gets the most out of both the nutrient and the water. Dissolved minerals in solution make the need for a conventional growth substrate relatively unnecessary in modern gardening applications. This can result in another way for gardeners to save.

Now let’s really get down to the bottom-line with this whole water angle:

Q: Sure seems like it takes a lot of plastic to make a hydroponics system … don’t they make that out of petroleum too?

This is without a doubt the least sustainable aspect to any plastic-intensive hydroponics application. Keep in mind, though, that the majority of soil cultivation is in plastic soil pots … which are often not reused. Most hydroponics systems incorporate as much recyclable content as possible in the form of HDPE (which currently has a LEED rating), PP (Poly Propylene) and other relatively benign plastics. At the present time there are no viable substitutes for PVC & ABS plastics. Hopefully in the not-so-distant future, plant-based polymers may offer a more sustainable substitute. When a hydroponics system is designed and built professionally it should be something that can be used for many, many years. It’s only over this period of time that the practicality of using the plastic finally balances out the negative impact of the plastic itself. With that said, avoid hydroponic plastics if you’ve no intention of reusing it over and over.

Some Conclusions

Whether you’re a fan of soil or water as your grow medium, one thing is for certain: producing consistently good results has to be the common denominator in any crop production strategy. There’s no shortage of different time tested techniques to get sound results. The ever-evolving challenge is how we can achieve the results we expect without disproportionately depleting our planet’s natural resources.

LEDs replacing HID grow lights within the next decade is pretty unlikely, but we can make responsible substitutions as these new technologies become available. Modern water culture methods are one of the most implementable techniques we can use to reduce our carbon footprint as growers. Though not perfect, water culture provides a genuinely organic grow medium at the turn of a wrist. Put down that bag and pick up the hose.

Some final food for thought:

Plant life as we know it conceivably evolved in the oceans long before our earth’s mantle was broken down into what we now consider soil. It was only when single-celled organisms came to the rocky shores of these primordial continents that terrestrial plants even began to exist.With that said, all plant life has its most ancient DNA, which is still able and very willing to adapt back to water. So if the seas were the Petri dish that plant life developed in, isn’t the ocean essentially just a constantly circulating, well-aerated solution of H2O and dissolved salts? Sound familiar?